Ion sources of various types are known. In such devices, an element or compound is dissociated and ionized in a plasma discharge process for use in an ion implantation apparatus. The ions are extracted from the source by means of electric extraction fields to provide a beam of charged particles. The beam includes the desired ions which are subsequently separated from the beam by mass charge separation techniques.
It is known in the art to have a filament inside a chamber formed by a shield to produce the ionization of the gas being utilized. The temperatures created by the ionization in such a chamber are very high and the quality of material which is required in the manufacture of the chamber is extensive resulting in high cost to produce such a chamber.
The filaments also are subjected to extremely high temperatures and do fail as a result. Down time lowers production and in view of the cost of such equipment, can be very costly.
This invention limits exposure from the ionization process to the filament and insulates the majority of the chamber by use of separate side and end walls and a separate top and bottom thus increasing the heat reflection into the center of the hot zone. The flow of the plasma is directed toward the aperture. The configuration of the chamber increases the heat reflection into the center of the hot zone and the configuration of the filament removes it from the hot zone. As a result, a truer beam is accomplished resulting in lower power consumption while creating greater consistency, and reducing non-burnt residue and increasing life span of components.